I mentioned a little bit that this membrane is not just lipid bilayer but there's also proteins that are inserted into the membrane.
我之前说过,这层膜不仅仅是一层脂质双分子层,而是有很多蛋白质嵌插在膜上的
They go across the membrane - this is the trans-membrane part of the receptor that's going across the membrane.
它们跨越式的存在于细胞膜上,这就是受体的跨膜部分,它跨越了细胞膜
Essentially, what they are is it's a protein that spans the membrane of a cell.
本质上来说,它是一个横跨细胞膜的蛋白质。
Now, this is in the resting state of all cells, there's some membrane potential and neurons have this resting membrane potential also.
现在这是一个静息状态的细胞,它具有膜电位,神经元也具有类似的静息电位
It's encased within a membrane, a cell membrane which we talked about the structure of.
都是膜包围细胞器,我们刚讲过其结构的那种膜
That results in a dramatic change in the membrane voltage; the potential across the membrane and that's shown here by this rapid rise in membrane potential.
变化导致了膜电压的剧烈变化,膜电压就是跨膜的电势差,表现为膜电位的迅速上升
Here is a thin membrane, it's a polymer scaffold, and on that polymer scaffold scientists have placed some skin cells and they've allowed it to grow.
这是一张薄膜,它是一个聚合物支架,在这个支架上,科学家放了一些皮肤细胞,并让它们生长
Now, that rapid rise is called depolarization and the membrane is said to be in a depolarized state because it's less polarized or less negatively charged repolarized as negatively charged.
这个迅速上升过程称为去极化,我们称膜处于去极化状态,因为膜的极化程度降低了,或者说是带的负电减少了,而复极化就代表重新带上负电荷
For now, just picture it in this simple way as a molecule, usually a protein, that's embedded in the cell membrane and many receptors have a part of them that is extracellular.
现在,我只把这种分子图示出来,受体通常是一种蛋白质,它们镶嵌在细胞膜上,很多受体还有部分结构露在细胞外
There's a local change in the membrane, that local change involves opening of channels that allow ions to pass through regions where they couldn't pass through before, that results in a change in voltage.
膜上会发生局部变化,局部变化包括离子通道开启,使离子通过,先前不能通过的区域,从而引起电压的变化
That happens, and if I was looking at a region of membrane that was experiencing an action potential I would see voltage change in just the way it's shown in this graph here.
当去极化发生时,如果我观察一个经历动作电位的区域,我就会看到这样的电压变化,就像这幅图上展示的一样
In some cells they're recycled, that is the cell is able to take up the neurotransmitter after it's released and restore it, but most often there are enzyme systems inside the pre-synaptic membrane where those neurotransmitters are synthesized.
在一些细胞中神经递质可以循环利用,这些细胞可以吸收,已经释放出的神经递质并重新储存起来,但更常见的是突触前膜中含有酶系统,在此合成神经递质
Because these molecules can span across the membrane from outside to inside, they're in just the right position to take messages that they receive from outside the cell and transmit them through the membrane into the cells internal apparatus, and that's what they do.
因为这些分子能穿过细胞膜,连通细胞内外,它们所在的位置非常适于接受信息,它们能将外界获得的信息,通过细胞膜传递给细胞器,这正是它们的功能
This is a picture of patch clamp, it's a device that engineers built to fasten onto individual cells in order to look at how molecules in the membrane of the cell are working, and I'll talk a little bit about that as we go along.
这是膜片钳的图片,工程师使用该装置固定单个细胞,由此观察,细胞膜中的分子怎样活动,在以后的课中我还会谈到这方面内容
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